Turntable drive



Dec. 8, 1953 p. B. JOHNSTON 2,551,627

" TURNTABLE DRIVE 2 Sheets-Sheet 1 Filed Oct. 30, 1951 INVENTOR .0. 5/706? day/Mira,

1366- 1953 D. B. JOHNSTON TURNTABLE DRIVE 2 Sheets-Sheet 2 Filed Oct; 50. 1951 The compensating drive mechanism embodying the present invention operates as follows: The

base plate l2 pivots on bearing sleeve 20 of bolt.

IS. The rollers l4 permit the base plate to pivot in a horizontal plane, but restrict movement of" the base plate in vertical planes. The ability of the drive mechanism to pivot in a horizontal plane allows the rubber wheels 28 to follow the circumference of drive ring 3| of turntable 33, and to be maintained in uninterrupted contact therewith.

This action of the drive mechanism is aided by means of spring 54 and the ability of rod 48 to slide freely in openings 52 and 53. This compensates for major variations in the curvature of the drive ring 3|. In addition to the foregoing assembly the driven unit 26 including the two rubber driving wheels 28 also pivots about the shaft 38. Th rubber wheels are spring-urged into engagement with the drive ring 3| to follow local irregularities in drive ring 30 such as may occur at the jointure of ring segments, and the construction of this assembly further ensures that the load transmitted by the spring 54 is equally divided between the two rubber wheels 28.

While I have shown and described the preferred embodiment of my invention, it will be understood that the latter may be embodied otherwise than as herein specifically illustrated or described, and that in the illustrated embodiment certain changes in the details of construction and in the arrangement of the parts may be made without departingfrom the underlying'idea or principle of the invention within the scope of the appended claims. 7

I claim:

1. In a drive mechanism for operating a turntable comprising a base plate, mounting means for said base plate, said mounting means being adapted to coact with said base plate to permit limited pivotal movement of said base plate in one plane but restrict movement in other planes, driving means mounted on said base plate, a driven unit also mounted for limited pivotal movement independent of said limited pivotal movement of said base plate, a rotating element in said drivenunit driven by said driving means and adapted to engage and rotate said turntable.

2. In a drive mechanism for operating a turntable comprising a drive ring secured to said turntable, a base plate, mounting means for said base plate, said mounting means being adapted to coact withsaid base plate to permit limited pivotal movement of said base plate in one plane but restrict movement-in other planes, driving means mounted on said base plate, a driven unit also mounted for limited pivotal movement independent of said limited pivotalmovement of said base plate, at least one wheel in said driven unit driven by said driving means and adapted to engage said drive ring to rotate said turntable.

3. In a drive mechanism for operating a turnsaid base plate, said mounting means being adapted to coact with said base plate to permit limited pivotal movement of said base plate in one plane but restrict movement in other planes, a motor on said base plate, a speed reduction mechanism on said base plate, a unit driven by said speed reduction mechanism and also mounted for limited pivotal movement independent of said limited pivotal movement of said base plate, a rotating element in said unit adapted to be spring-urged into engagement. with said turntable to rotate said turntable.

4. In a drive mechanism for operating a turntable comprising a base plate, mounting means for said base plate, said mounting means including atleast one pair of rollers, said base plate being positioned between said pair of rollers to permit limited'pivotal movement of said base plate in one plane but restrict movement in other planes, a motor on said base plate, a speed reduction mechanism on said base plate, a unit driven by said speed reduction mechanism and also mounted for-limited pivotal movement independent of said limited pivotal movement of said base plate, a rotating element in said unit driven by said speed reduction mechanism and adapted to engage and rotate said turntable.

5. In a drive mechanism for operating a turntable, a drive ring secured to said turntable, a base plate, mounting means for said base plate, said mounting means including at least one pair of rollers, said base plate being positioned between said pair of rollers to permit limited pivotal movement in one plane but restrict'movement in other planes, driving means mounted on said base plate, a driven unit also mounted for limited pivotal movement independentof said limited plate in one plane but restrict movement in other planes, said base plate being adapted to pivot at a point remote from said rollers, driving means mounted on said base plate, a driven unit also 'mounted for limited pivotal movement, a rotating element in said driven unit driven by said driving means and adapted to engage and rotate said turntable. I

7. In a drive mechanism for operating a turntable, a frame member, a movable base plate,

'mounting means for said base plate, said mounting means being adapted to maintain said base plate in substantially parallel-spaced relation to said frame member and to coact with said base plate to permit limited pivotal movement of said base plate relative to said frame member in a horizontal plane but restrict movement in other planes, driving means mounted on said base plate, a driven unit also mounted for limitedpivotal movement independent of said limited pivotal movementof said base plate, a rotating element in said driven unit driven by said driving means and means mounted on said frame member for urging said rotating element into engagement with said turntable. .8. In a drive mechanism for operating a turntable comprising a base, plate, mounting means for said'base plate, said mounting'means being ;adapted to coact with said'baseplate :to permit limited pivotal movement of said base plate in one plane but restrict movement in other planes, driving means mounted on said base plate, a driven unit having a pair of wheels pivotally mounted on said base plate at a point located between said wheels, said Wheels being mounted for limited pivotal movement as a unit independent of the pivotal movement of said base plate, said wheels being driven by said driving means and adapted to engage and rotate said turntable.

9. In a drive mechanism for operating a turntable comprising a base plate, mounting means for said base plate, said mounting means being adapted to coact with said base plate to permit limited pivotal movement of said base plate in one plane but restrict movement in other planes, roller means being positioned on an edge portion of said base plate, said base plate being adapted for limited pivotal movement therebetween, driving means mounted on said base plate, a driven unit on said base plate having a pair of wheels pivoting on said base plate at a point located between said pair of Wheels, said unit being propelled by said driving means and adapted to engage and rotate said turntable.

D. BRUCE JOHNSTON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 758,323 Lindquist Apr. 1904 1,496,120 r Hilger June 3, 1924: ,3 Weiss Dec. 16, 1941 2,421,910 Hartman June 10, 1947 2,566,674 Odenthal Sept. 1951 

